Driver fatigue warning system

ABSTRACT

A driver-fatigue warning system suitable for use in an automated vehicle includes a camera, an alert-device, and a controller. The camera renders an image of a lane-marking and of an object proximate to a host-vehicle. The alert-device is operable to alert an operator of the host-vehicle of driver-fatigue. The controller is in communication with the camera and the alert-device. The controller determines a vehicle-offset of the host-vehicle relative to the lane-marking based on the image. The controller determines an offset-position of the object relative to the lane-marking based on the image. The controller determines that a lane-departure has occurred when the vehicle-offset is less than a deviation-threshold. The controller does not count occurrences of lane-departures when the offset-position is less than an offset-threshold, and activates the alert-device when the count of the occurrences of lane-departures exceeds a crossing-threshold indicative of driver-fatigue.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional application and claims the benefit under 35 U.S.C.§ 121 of U.S. patent application Ser. No. 15/611,273, filed Jun. 1,2017, the entire disclosure of which is hereby incorporated herein byreference.

TECHNICAL FIELD OF INVENTION

This disclosure generally relates to a driver-fatigue warning system,and more particularly relates to a driver-fatigue warning system thatdoes not penalize a driver for avoiding an object.

BACKGROUND OF INVENTION

It is known to detect a driver's level of fatigue by tracking alane-keeping-performance that determines how well a driver maintains alane-position. Excessive movement within a lane and/or excessivelane-departures may indicate an unsafe level of driver-fatigue and maylead to an activation of an alert-device that alerts the driver to theirlowered level of responsiveness.

SUMMARY OF THE INVENTION

In accordance with one embodiment, a driver-fatigue warning system isprovided. The driver-fatigue warning system suitable for use in anautomated vehicle includes a camera, an alert-device, and a controller.The camera renders an image of a lane-marking and of an object proximateto a host-vehicle. The alert-device is operable to alert an operator ofthe host-vehicle of driver-fatigue. The controller is in communicationwith the camera and the alert-device. The controller determines avehicle-offset of the host-vehicle relative to the lane-marking based onthe image. The controller determines an offset-position of the objectrelative to the lane-marking based on the image. The controllerdetermines that a lane-departure has occurred when the vehicle-offset isless than a deviation-threshold. The controller does not countoccurrences of lane-departures when the offset-position is less than anoffset-threshold, and activates the alert-device when the count of theoccurrences of lane-departures exceeds a crossing-threshold indicativeof driver-fatigue.

In another embodiment, a method of operating a driver-fatigue warningsystem suitable for use in an automated vehicle is provided. The methodincludes the steps of rendering an image, alerting an operator,determining a vehicle-offset, determining a lane-departure, determiningan offset-position, and activating an alert-device. The step ofrendering an image, may include rendering, with a camera, an image of alane-marking and of an object proximate to a host-vehicle. The step ofalerting an operator, may include, alerting, with an alert-device, anoperator of the host-vehicle of driver-fatigue. The step of determiningthe vehicle-offset, may include determining, with a controller incommunication with the camera and the alert-device, the vehicle-offsetof the host-vehicle relative to the lane-marking based on the image. Thestep of determining the offset-position, may include determining theoffset-position of the object relative to the lane-marking based on theimage. The step of determining the lane-departure, may includedetermining that the lane-departure has occurred when the vehicle-offsetis less than a deviation-threshold, and not counting occurrences oflane-departures when the offset-position is less than anoffset-threshold. The step of activating the alert-device, may includeactivating the alert-device when the count of the occurrences oflane-departures exceeds a crossing-threshold indicative ofdriver-fatigue.

In yet another embodiment, an automated vehicular warning system isprovided. The automated vehicular warning system includes a camera, analert-device, and a controller in communication with the camera and thealert-device. The controller counts a lane-departure of a host-vehiclewhen a host-vehicle-offset relative to a lane-marking is less than athreshold. The controller does not count the lane-departure when anobject in a roadway urges an operator of the host-vehicle to perform thelane-departure. The controller activates the alert-device when the countof the lane-departures exceeds a departure-threshold.

Further features and advantages will appear more clearly on a reading ofthe following detailed description of the preferred embodiment, which isgiven by way of non-limiting example only and with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will now be described, by way of example withreference to the accompanying drawings, in which:

FIG. 1 is an illustration of a driver-fatigue warning system inaccordance with one embodiment;

FIG. 2 is an illustration of a host-vehicle equipped with thedriver-fatigue warning system of FIG. 1 making a lane-departure inaccordance with one embodiment;

FIG. 3 is an illustration of the host-vehicle of FIG. 2 making alane-departure in accordance with one embodiment;

FIG. 4 is an illustration of the host-vehicle of FIG. 2 making alane-departure in accordance with one embodiment;

FIG. 5 is an illustration of the host-vehicle of FIG. 2 making alane-departure in accordance with one embodiment;

FIG. 6 is a flow chart of a method of operating a driver-fatigue warningsystem in accordance with another embodiment;

FIG. 7 is an illustration of an automated vehicular warning system inaccordance with yet another embodiment;

FIG. 8 is an illustration of a host-vehicle equipped with the automatedvehicular warning system of FIG. 7 making a lane-departure in accordancewith yet another embodiment;

FIG. 9 is an illustration of the host-vehicle of FIG. 8 making alane-departure in accordance with yet another embodiment;

FIG. 10 is an illustration of the host-vehicle of FIG. 8 making alane-departure in accordance with yet another embodiment;

FIG. 11 is an illustration of the host-vehicle of FIG. 8 making alane-departure in accordance with yet another embodiment; and

FIG. 12 is a flow chart of a driver-fatigue algorithm in accordance withone embodiment.

DETAILED DESCRIPTION

A typical driver-fatigue system detects whether an operator of ahost-vehicle is drowsy or fatigued by measuring alane-keeping-performance. The typical lane-keeping-performance algorithmestimates an operator's ability to drive the host-vehicle along acenterline of a travel-lane by detecting certain sequences of events,and/or a lack of steering-activity. Events that are indicative ofdriver-fatigue include, but are not limited to, a variation in alateral-offset of the host-vehicle from the centerline, and/or nosteering-activity while the host-vehicle drifts away from the centerlinefollowed by a sudden steering-correction back to the centerline (a.k.a.Swivel). It is known in the art that a significant increase in a numberof lane-crossings, without the use of signaling, may be an indicator ofdriver-fatigue.

While the typical lane-keeping-performance algorithm may accuratelyestimate the driver-fatigue under ideal traffic conditions, situationsexist where the operator may intentionally perform a lane-departure toavoid an object in an adjacent-lane or on a shoulder of a roadway (e.g.an oversize-load being transported or an other-vehicle stopped on theshoulder), or to avoid an object in the travel-lane (e.g. a pot-hole ordebris). While these lane-departures may be associated with cautiousand/or courteous driving maneuvers, they may be counted by the typicallane-keeping-performance algorithm as an indication of driver-fatigue,and may lead to a false driver-fatigue warning. As will be described inmore detail below, the system described herein is an improvement overprior driver-fatigue warning systems because the system reduces therates of the false driver-fatigue warning by determining when to countthe lane-departure, which may help to reduce occurrences of operatorsintentionally deactivating the driver-fatigue warning system.

FIG. 1 illustrates a non-limiting example of a driver-fatigue warningsystem 10, hereafter referred to as the system 10, suitable for use inan automated vehicle 12, hereafter referred to as a host-vehicle 12. Asused herein, the term ‘automated vehicle’ is not meant to suggest thatfully automated or autonomous operation of the host-vehicle 12 isrequired. It is contemplated that the teachings presented herein areapplicable to instances where the host-vehicle 12 is entirely manuallyoperated by a human and the automation is merely providing emergencybraking to the human. The system 10 includes a camera 14 that renders animage 16 of a lane-marking 18 of a roadway 20 and of an object 22proximate to the host-vehicle 12. Examples of the camera 14 suitable foruse on the host-vehicle 12 are commercially available as will berecognized by those in the art, one such being the APTINA MT9V023 fromMicron Technology, Inc. of Boise, Id., USA. The camera 14 may be mountedon the front of the host-vehicle 12, or mounted in the interior of thehost-vehicle 12 at a location suitable for the camera 14 to view thearea around the host-vehicle 12 through the windshield of thehost-vehicle 12. The camera 14 is preferably a video-type camera 14 orcamera 14 that can capture images 16 of the roadway 20 and surroundingarea at a sufficient frame-rate, of ten frames per second, for example.A travel-lane 24 may be defined by the lane-markings 18, or may bedefined by edges of pavement if no lane-markings 18 are detected. Theimage 16 may include, but is not limited to, the lane-marking 18 on aleft-side and on a right-side of the travel-lane 24 of the roadway 20.The image 16 may also include the lane-marking 18 in an adjacent-lane26. The lane-marking 18 may include a solid-line, a dashed-line, or anycombination thereof.

The system 10 also includes an alert-device 28 operable to alert anoperator 30 of the host-vehicle 12 of driver-fatigue. The alert-device28 may be an indicator viewable by the operator 30 that is illuminatedto indicate an instance of driver-fatigue, and/or an audible alarm,and/or a vibratory alarm that is activated to indicate the same.

The system 10 also includes a controller 32 in communication with thecamera 14 and the alert-device 28. The controller 32 may include aprocessor (not shown) such as a microprocessor or other controlcircuitry such as analog and/or digital control circuitry including anapplication specific integrated circuit (ASIC) for processing data asshould be evident to those in the art. The controller 32 may include amemory (not specifically shown), including non-volatile memory, such aselectrically erasable programmable read-only memory (EEPROM) for storingone or more routines, thresholds, and captured data. The one or moreroutines may be executed by the processor to perform steps fordetermining if a detected instance of driver-fatigue exists based onsignals received by the controller 32 from the camera 14 as describedherein.

The controller 32 may receive the image 16, via a video-signal (notshown), and may determine both a lane-width (not specifically shown) anda centerline 34 of the travel-lane 24 based on the lane-marking 18. Thatis, the image 16 detected or captured by the camera 14 is processed bythe controller 32 using known techniques for image-analysis to determinewhere along the roadway 20 the host-vehicle 12 should be operated or besteered. Vision processing technologies, such as the EyeQ® platform fromMoblieye Vision Technologies, Ltd. of Jerusalem, Israel, or othersuitable devices may be used. By way of example and not limitation, thecenterline 34 is preferably in the middle of the travel-lane 24 traveledby the host-vehicle 12.

FIG. 2 illustrates a traffic scenario where the host-vehicle 12 isapproaching the object 22 (i.e. an oversize-load) that is traveling inthe adjacent-lane 26. The operator 30 of the host-vehicle 12 makes anintentional lane-departure 38, as is indicated by a perimeter of thehost-vehicle 12 overlaying the lane-marking 18 on the left-side of thetravel-lane 24, to provide greater clearance between the host-vehicle 12and the object 22. The controller 32 determines a vehicle-offset 36 ofthe host-vehicle 12 relative to the lane-marking 18 based on the image16 received from the camera 14. The vehicle-offset 36 is a measure of adistance from both a left-side and a right-side of the host-vehicle 12to the lane-marking 18. The controller 32 determines that thelane-departure 38 has occurred when the vehicle-offset 36 is less than adeviation-threshold 40. The deviation-threshold 40 as used herein isdefined as a minimum allowable distance from the left-side and/or theright-side of the host-vehicle 12 to the lane-marking 18. Thedeviation-threshold 40 may be user-defined and may be any distanceneeded to meet the requirements of the host-vehicle 12, and may be in arange from between zero meters (0.0 meters) to 0.75 meters. Thedeviation-threshold 40 may vary based on a width of the host-vehicle 12and/or may vary based on the width of the travel-lane 24. An occurrenceof the lane-departure 38 may be counted 42 by the controller 32 and maybe stored in the memory for estimating the operator's 30lane-keeping-performance.

As illustrated in FIG. 2, the controller 32 also determines anoffset-position 44 of the object 22 relative to the lane-marking 18based on the image 16. The offset-position 44 is defined as the distancefrom either the left-side or the right-side of the object 22 to thelane-marking 18 of the travel-lane 24 traveled by the host-vehicle 12.The controller 32 also determines an offset-threshold 46 defined as theminimum allowable distance from the left-side and/or the right-side ofthe object 22 to the lane-marking 18 of the travel-lane 24 traveled bythe host-vehicle 12 (shown on the left-side of the object 22 in FIG. 2for illustration purposes only). The offset-threshold 46 may beuser-defined and may be any distance needed to meet the requirements ofthe host-vehicle 12, and may be in the range from between 0.0 meters to0.75 meters. The offset-threshold 46 may vary based on a width of theobject 22 and/or may vary based on the width of the travel-lane 24,and/or may vary based on the width of the host-vehicle 12.

The controller 32 does not count occurrences of the lane-departures 38of the host-vehicle 12 when the offset-position 44 is less than theoffset-threshold 46 as illustrated in FIG. 2. By not counting 42 theoccurrences of the lane-departures 38 under the aforementionedconditions, the system 10 does not penalize the operator 30 of thehost-vehicle 12 when the operator 30 makes an intentional lane-departure38 to provide greater clearance between the host-vehicle 12 and thedetected object 22.

FIG. 3 illustrates another traffic scenario where the operator 30 of thehost-vehicle 12 makes the intentional lane-departure 38 in to providegreater clearance between the host-vehicle 12 and the detected object 22(e.g. a pot-hole and/or debris) located in the travel-lane 24 traveledby the host-vehicle 12 that is perceived as a hazard by the operator 30.As illustrated in FIG. 3, the operator 30 makes the lane-departure 38 tothe left-side of the travel-lane 24. The controller 32 does not countthe occurrence of the lane-departure 38 when the offset-position 44(illustrated as a negative value of distance from the lane-marking 18)is less than the offset-threshold 46 as illustrated in FIG. 3. Thelocation of the detected object 22 may urge the operator 30 to make theintentional lane-departure 38 to either-side of the object 22 and willnot be counted 42 by the controller 32.

FIG. 4 illustrates yet another traffic scenario where the operator 30 ofthe host-vehicle 12 makes the intentional lane-departure 38 to providegreater clearance between the host-vehicle 12 and the detected object 22(e.g. construction pylons) located on the shoulder of the travel-lane 24that are perceived as the hazard by the operator 30. As illustrated inFIG. 4, the operator 30 is making the lane-departure 38 to the left-sideof the travel-lane 24. The controller 32 does not count the occurrenceof the lane-departure 38 when the offset-position 44 is less than theoffset-threshold 46.

FIG. 5 illustrates yet another traffic scenario where the controller 32further determines that the object 22 (e.g. the oversize-load) is in theadjacent-lane 26, and determines that the lane-departure 38 also occursinto the adjacent-lane 26. In contrast to the traffic scenarioillustrated in FIG. 2, the controller 32 counts 42 the lane-departure 38illustrated in FIG. 5 because the host-vehicle 12 moves closer to theobject 22 without signaling the maneuver, which may be indicative ofdriver-fatigue.

The controller 32 activates the alert-device 28 when the count 42 of theoccurrences of lane-departures 38 exceeds a crossing-threshold 48 (seeFIG. 1) indicative of driver-fatigue. The crossing-threshold 48 may beany number of occurrences of lane-departures 38 within a definedtime-period, and is preferably in the range from between 2 to 3lane-departures 38 within the time-period of two minutes.

Returning to FIG. 1, the system 10 may further include a ranging-sensor50 in communication with the controller 32. The ranging-sensor 50 maydetect a range 52, and an azimuth-angle 54 of the object 22 relative toa host-vehicle-longitudinal-axis (not shown). The ranging-sensor 50 maybe a radar 56 such as the radar-sensor from Delphi Inc. of Troy, Mich.,USA and marketed as an Electronically Scanning Radar (ESR) or aRear-Side-Detection-System (RSDS), or Short-Range-Radar (SRR) or theranging-sensor 50 may be a lidar 58, or the ranging-sensor 50 may be anultrasonic-transducer 60 such as the TIDA-00151 from Texas Instrumentsof Dallas, Tex., USA. The controller 32 may further determine theoffset-position 44 of the object 22 based on the range 52 and theazimuth-angle 54, as will be understood by those in the art.

FIG. 6 illustrates a non-limiting example of a method 200 of operating adriver-fatigue warning system 10 illustrated in FIG. 1, hereafterreferred to as the system 10, suitable for use in an automated vehicle,hereafter referred to as a host-vehicle 12. As used herein, the term‘automated vehicle’ is not meant to suggest that fully automated orautonomous operation of the host-vehicle 12 is required. It iscontemplated that the teachings presented herein are applicable toinstances where the host-vehicle 12 is entirely manually operated by ahuman and the automation is merely providing emergency braking to thehuman.

Step 202, RENDER IMAGE, may include the step of rendering, with a camera14, an image 16 of a lane-marking 18 of a roadway 20 and of an object 22proximate to the host-vehicle 12. Examples of the camera 14 suitable foruse on the host-vehicle 12 are commercially available as will berecognized by those in the art, one such being the APTINA MT9V023 fromMicron Technology, Inc. of Boise, Id., USA. The camera 14 may be mountedon the front of the host-vehicle 12, or mounted in the interior of thehost-vehicle 12 at a location suitable for the camera 14 to view thearea around the host-vehicle 12 through the windshield of thehost-vehicle 12. The camera 14 is preferably a video-type camera 14 orcamera 14 that can capture images 16 of the roadway 20 and surroundingarea at a sufficient frame-rate, of ten frames per second, for example.A travel-lane 24 may be defined by the lane-markings 18, or may bedefined by edges of pavement if no lane-markings 18 are detected. Theimage 16 may include, but is not limited to, the lane-marking 18 on aleft-side and on a right-side of the travel-lane 24 of the roadway 20.The image 16 may also include the lane-marking 18 in an adjacent-lane26. The lane-marking 18 may include a solid-line, a dashed-line, or anycombination thereof.

Step 204, ALERT OPERATOR, may include the step of alerting, with analert-device 28, an operator 30 of the host-vehicle 12 ofdriver-fatigue. The alert-device 28 may be an indicator viewable by theoperator 30 that is illuminated to indicate an instance ofdriver-fatigue, and/or an audible alarm, and/or a vibratory alarm thatis activated to indicate the same.

Step 206, DETERMINE VEHICLE-OFFSET, may include determining, with acontroller 32 in communication with the camera 14 and the alert-device28, a vehicle-offset 36 of the host-vehicle 12 relative to thelane-marking 18 based on the image 16. The controller 32 may include aprocessor (not shown) such as a microprocessor or other controlcircuitry such as analog and/or digital control circuitry including anapplication specific integrated circuit (ASIC) for processing data asshould be evident to those in the art. The controller 32 may include amemory (not specifically shown), including non-volatile memory, such aselectrically erasable programmable read-only memory (EEPROM) for storingone or more routines, thresholds, and captured data. The one or moreroutines may be executed by the processor to perform steps fordetermining if a detected instance of driver-fatigue exists based onsignals received by the controller 32 from the camera 14 as describedherein.

The controller 32 may receive the image 16, via a video-signal (notshown), and may determine both a lane-width (not specifically shown) anda centerline 34 of the travel-lane 24 based on the lane-marking 18. Thatis, the image 16 detected or captured by the camera 14 is processed bythe controller 32 using known techniques for image-analysis to determinewhere along the roadway 20 the host-vehicle 12 should be operated or besteered. Vision processing technologies, such as the EyeQ® platform fromMoblieye Vision Technologies, Ltd. of Jerusalem, Israel, or othersuitable devices may be used. By way of example and not limitation, thecenterline 34 is preferably in the middle of the travel-lane 24 traveledby the host-vehicle 12.

FIG. 2 illustrates a traffic scenario where the host-vehicle 12 isapproaching the object 22 (i.e. an oversize-load) that is traveling inthe adjacent-lane 26. The operator 30 of the host-vehicle 12 makes anintentional lane-departure 38, as is indicated by a perimeter of thehost-vehicle 12 overlaying the lane-marking 18 on the left-side of thetravel-lane 24, to provide greater clearance between the host-vehicle 12and the object 22. The controller 32 determines the vehicle-offset 36 ofthe host-vehicle 12 relative to the lane-marking 18 based on the image16 received from the camera 14. The vehicle-offset 36 is a measure of adistance from both a left-side and a right-side (not specifically shown)of the host-vehicle 12 to the lane-marking 18.

Step 208, DETERMINE LANE-DEPARTURE, may include the step of determining,with the controller 32, that the lane-departure 38 has occurred when thevehicle-offset 36 is less than a deviation-threshold 40. Thedeviation-threshold 40 as used herein is defined as a minimum allowabledistance from the left-side and/or the right-side of the host-vehicle 12to the lane-marking 18. The deviation-threshold 40 may be user-definedand may be any distance needed to meet the requirements of thehost-vehicle 12, and may be in a range from between zero meters (0.0meters) to 0.75 meters. The deviation-threshold 40 may vary based on awidth of the host-vehicle 12 and/or may vary based on the width of thetravel-lane 24. An occurrence of the lane-departure 38 may be counted 42by the controller 32 and may be stored in the memory for estimating theoperator's 30 lane-keeping-performance.

Step 210, DETERMINE OFFSET-POSITION, may include the step ofdetermining, with the controller 32, an offset-position 44 of the object22 relative to the lane-marking 18 based on the image 16. Theoffset-position 44 is defined as the distance from either the left-sideor the right-side of the object 22 to the lane-marking 18 of thetravel-lane 24 traveled by the host-vehicle 12. The controller alsodetermines an offset-threshold 46 defined as the minimum allowabledistance from the left-side and/or the right-side of the object 22 tothe lane-marking 18 of the travel-lane 24 traveled by the host-vehicle12 (shown only on the left-side of the object 22 in FIG. 2 forillustration purposes only). The offset-threshold 46 may be user-definedand may be any distance needed to meet the requirements of thehost-vehicle 12, and may be in the range from between 0.0 meters to 0.75meters. The offset-threshold 46 may vary based on a width of the object22 and/or may vary based on the width of the travel-lane 24, and/or mayvary based on the width of the host-vehicle 12.

The controller 32 does not count occurrences of the lane-departures 38of the host-vehicle 12 when the offset-position 44 is less than theoffset-threshold 46 as illustrated in FIG. 2. By not counting 42 theoccurrences of the lane-departures 38 under the aforementionedconditions, the system 10 does not penalize the operator 30 of thehost-vehicle 12 when the operator 30 makes an intentional lane-departure38 to provide greater clearance between the host-vehicle 12 and thedetected object 22.

FIG. 3 illustrates another traffic scenario where the operator 30 of thehost-vehicle 12 makes the intentional lane-departure 38 to providegreater clearance between the host-vehicle 12 and the detected object 22(e.g. a pot-hole and/or debris) located in the travel-lane 24 traveledby the host-vehicle 12 that is perceived as a hazard by the operator 30.As illustrated in FIG. 3, the operator 30 makes the lane-departure 38 tothe left-side of the travel-lane 24. The controller 32 does not countthe occurrence of the lane-departure 38 when the offset-position 44(illustrated as a negative value of distance from the lane-marking 18)is less than the offset-threshold 46 as illustrated in FIG. 3. Thelocation of the detected object 22 may urge the operator 30 to make theintentional lane-departure 38 to either-side of the object 22 and willnot be counted 42 by the controller 32.

FIG. 4 illustrates yet another traffic scenario where the operator 30 ofthe host-vehicle 12 makes the intentional lane-departure 38 to providegreater clearance between the host-vehicle 12 and the detected object 22(e.g. construction pylons) located on the shoulder of the travel-lane 24that are perceived as the hazard by the operator 30. As illustrated inFIG. 4, the operator 30 is making the lane-departure 38 to the left-sideof the travel-lane 24. The controller 32 does not count the occurrenceof the lane-departure 38 when the offset-position 44 is less than theoffset-threshold 46.

FIG. 5 illustrates yet another traffic scenario where the controller 32further determines that the object 22 (e.g. the oversize-load) is in theadjacent-lane 26, and determines that the lane-departure 38 also occursinto the adjacent-lane 26. In contrast to the traffic scenarioillustrated in FIG. 2, the controller 32 counts 42 the lane-departure 38illustrated in FIG. 5 because the host-vehicle 12 moves closer to theobject 22 without signaling the maneuver, which may be indicative ofdriver-fatigue.

Step 212, ACTIVATE ALERT-DEVICE, may include the step of activating,with the controller 32, the alert-device 28 when the count 42 of theoccurrences of lane-departures 38 exceeds a crossing-threshold 48 (seeFIG. 1) indicative of driver-fatigue. The crossing-threshold 48 may beany number of occurrences of lane-departures 38 within a definedtime-period, and is preferably in the range from between 2 to 3lane-departures 38 within the time-period of two minutes.

Returning to FIG. 1, the system 10 may further include a ranging-sensor50 in communication with the controller 32. The ranging-sensor 50 maydetect a range 52, and an azimuth-angle 54 of the object 22 relative toa host-vehicle-longitudinal-axis (not shown). The ranging-sensor 50 maybe a radar 56 such as the radar-sensor from Delphi Inc. of Troy, Mich.,USA and marketed as an Electronically Scanning Radar (ESR) or aRear-Side-Detection-System (RSDS), or Short-Range-Radar (SRR), or theranging-sensor 50 may be a lidar 58, or the ranging-sensor 50 may be anultrasonic-transducer 60 such as the TIDA-00151 from Texas Instrumentsof Dallas, Tex., USA. The controller 32 may further determine theoffset-position 44 of the object 22 based on the range 52 and theazimuth-angle 54, as will be understood by those in the art.

FIG. 7 is a non-limiting example of yet another embodiment of anautomated vehicular warning system 110, hereafter referred to as thesystem 110, suitable for use on an automated vehicle 112, hereafterreferred to as a host-vehicle 112. As used herein, the term ‘automatedvehicle’ is not meant to suggest that fully automated or autonomousoperation of the host-vehicle 112 is required. It is contemplated thatthe teachings presented herein are applicable to instances where thehost-vehicle 112 is entirely manually operated by a human and theautomation is merely providing emergency braking to the human. Thesystem 110 includes a camera 114 that renders an image 116 of alane-marking 118 of a roadway 120 and of an object 122 proximate to thehost-vehicle 112. Examples of the camera 114 suitable for use on thehost-vehicle 112 are commercially available as will be recognized bythose in the art, one such being the APTINA MT9V023 from MicronTechnology, Inc. of Boise, Id., USA. The camera 114 may be mounted onthe front of the host-vehicle 112, or mounted in the interior of thehost-vehicle 112 at a location suitable for the camera 114 to view thearea around the host-vehicle 112 through the windshield of thehost-vehicle 112. The camera 114 is preferably a video-type camera 114or camera 114 that can capture images 116 of the roadway 120 andsurrounding area at a sufficient frame-rate, of ten frames per second,for example. A travel-lane 124 may be defined by the lane-markings 118,or may be defined by edges of pavement if no lane-markings 118 aredetected. The image 116 may include, but is not limited to, thelane-marking 118 on a left-side and on a right-side of the travel-lane124 of the roadway 120. The image 116 may also include the lane-marking118 in an adjacent-lane 126. The lane-marking 118 may include asolid-line, a dashed-line, or any combination thereof.

The system 110 also includes an alert-device 128 operable to alert anoperator 130 of the host-vehicle 112 of driver-fatigue. The alert-device128 may be an indicator viewable by the operator 130 that is illuminatedto indicate an instance of driver-fatigue, and/or an audible alarm,and/or a vibratory alarm that is activated to indicate the same.

The system 110 also includes a controller 132 in communication with thecamera 114 and the alert-device 128. The controller 132 may include aprocessor (not shown) such as a microprocessor or other controlcircuitry such as analog and/or digital control circuitry including anapplication specific integrated circuit (ASIC) for processing data asshould be evident to those in the art. The controller 132 may include amemory (not specifically shown), including non-volatile memory, such aselectrically erasable programmable read-only memory (EEPROM) for storingone or more routines, thresholds, and captured data. The one or moreroutines may be executed by the processor to perform steps fordetermining if a detected instance of driver-fatigue exists based onsignals received by the controller 132 from the camera 114 as describedherein.

The controller 132 may receive the image 116, via a video-signal (notshown), and may determine both a lane-width (not specifically shown) anda centerline 134 of the travel-lane 124 based on the lane-marking 118.That is, the image 116 detected or captured by the camera 114 isprocessed by the controller 132 using known techniques forimage-analysis to determine where along the roadway 120 the host-vehicle112 should be operated or be steered. Vision processing technologies,such as the EyeQ® platform from Moblieye Vision Technologies, Ltd. ofJerusalem, Israel, or other suitable devices may be used. By way ofexample and not limitation, the centerline 134 is preferably in themiddle of the travel-lane 124 traveled by the host-vehicle 112.

FIG. 8 illustrates a traffic scenario where the host-vehicle 112 isapproaching the object 122 (i.e. an oversize-load) that is traveling inthe adjacent-lane 126. The operator 130 of the host-vehicle 112 makes anintentional lane-departure 138, as is indicated by a perimeter of thehost-vehicle 112 overlaying the lane-marking 118 on the left-side of thetravel-lane 124, to provide greater clearance between the host-vehicle112 and the object 22. The controller 132 determines ahost-vehicle-offset 136 of the host-vehicle 112 relative to thelane-marking 118 based on the image 116 received from the camera 114.The host-vehicle-offset 136 is a measure of a distance (not specificallyshown) from both a left-side and a right-side (not specifically shown)of the host-vehicle 112 to the lane-marking 118. The controller 132determines that the lane-departure 138 has occurred when thehost-vehicle-offset 136 is less than a threshold 140. The threshold 140as used herein is defined as a minimum allowable distance from theleft-side and/or the right-side of the host-vehicle 112 to thelane-marking 118. The threshold 140 may be user-defined and may be anydistance needed to meet the requirements of the host-vehicle 112, andmay be in a range from between zero meters (0.0 meters) to 0.75 meters.The threshold 140 may vary based on a width of the host-vehicle 112and/or may vary based on the width of the travel-lane 124. An occurrenceof the lane-departure 138 may be counted 142 by the controller 132 andmay be stored in the memory for estimating the operator's 130lane-keeping-performance.

As illustrated in FIG. 8, the controller 132 also determines anoffset-position 144 of the object 122 relative to the lane-marking 118based on the image 116. The offset-position 144 is defined as thedistance from either the left-side or the right-side of the object 122to the lane-marking 118 of the travel-lane 124 traveled by thehost-vehicle 112. The controller 132 also determines an offset-threshold146 defined as the minimum allowable distance from the left-side and/orthe right-side of the object 122 to the lane-marking 118 of thetravel-lane 24 traveled by the host-vehicle 12 (shown on the left-sideof the object 122 in FIG. 8 for illustration purposes only). Theoffset-threshold 146 may be user-defined and may be any distance neededto meet the requirements of the host-vehicle 112, and may be in therange from between 0.0 meters to 0.75 meters. The offset-threshold 146may vary based on a width of the object 122 and/or may vary based on thewidth of the travel-lane 124, and/or may vary based on the width of thehost-vehicle 112.

The controller 132 does not count 142 occurrences of the lane-departures138 of the host-vehicle 112 when the offset-position 144 is less thanthe offset-threshold 146 as illustrated in FIG. 8 By not counting 142the occurrences of the lane-departures 138 under the aforementionedconditions, the system 110 does not penalize the operator 130 of thehost-vehicle 112 when the operator 130 makes an intentionallane-departure 138 to provide greater clearance between the host-vehicle112 and the detected object 122.

FIG. 9 illustrates another traffic scenario where the operator 130 ofthe host-vehicle 112 makes the intentional lane-departure 138 to providegreater clearance between the host-vehicle 112 and the detected object122 (e.g. a pot-hole and/or debris) located in the travel-lane 124traveled by the host-vehicle 112 that is perceived as a hazard by theoperator 130. As illustrated in FIG. 9, the operator 130 is making thelane-departure 138 to the left-side of the travel-lane 124. Thecontroller 132 does not count 142 the occurrence of the lane-departure138 when the offset-position 144 (illustrated as a negative value ofdistance from the lane-marking 118) is less than the offset-threshold146 as illustrated in FIG. 9. The location of the detected object 122may urge the operator 30 to make the intentional lane-departure 138 toeither-side of the object 122 and will not be counted 142 by thecontroller 132.

FIG. 10 illustrates yet another traffic scenario where the operator 130of the host-vehicle 112 makes the intentional lane-departure 138 toprovide greater clearance between the host-vehicle 112 and the detectedobject 122 (e.g. construction pylons) located on the shoulder of thetravel-lane 124 that are perceived as the hazard by the operator 130. Asillustrated in FIG. 10, the operator 130 is making the lane-departure138 to the left-side of the travel-lane 124. The controller 132 does notcount 142 the occurrence of the lane-departure 138 when theoffset-position 144 is less than the offset-threshold 146.

FIG. 11 illustrates yet another traffic scenario where the controller132 further determines that the object 122 (e.g. the oversize-load) isin the adjacent-lane 126, and determines that the lane-departure 138also occurs into the adjacent-lane 126. In contrast to the trafficscenario illustrated in FIG. 8, the controller 132 counts 142 thelane-departure 138 illustrated in FIG. 11 because the host-vehicle 112moves closer to the object 122 without signaling the maneuver, which maybe indicative of driver-fatigue.

The controller 132 activates the alert-device 128 when the count 142 ofthe occurrences of lane-departures 138 exceeds a departure-threshold 148(see FIG. 7) indicative of driver-fatigue. The departure-threshold 148may be any number of occurrences of lane-departures 138 within a definedtime-period, and is preferably in the range from between 2 to 3lane-departures 138 within the time-period of two minutes.

Returning to FIG. 7, the system 110 may further include a ranging-sensor150 in communication with the controller 132. The ranging-sensor 150 maydetect a range 152, and an azimuth-angle 154 of the object 122 relativeto a host-vehicle-longitudinal-axis (not shown). The ranging-sensor 150may be a radar 156 such as the radar-sensor from Delphi Inc. of Troy,Mich., USA and marketed as an Electronically Scanning Radar (ESR) or aRear-Side-Detection-System (RSDS), or Short-Range-Radar (SRR), or theranging-sensor 150 may be a lidar 158, or the ranging-sensor 150 may bean ultrasonic-transducer 160 such as the TIDA-00151 from TexasInstruments of Dallas, Tex., USA. The controller 132 may furtherdetermine the offset-position 144 of the object 122 based on the range152 and the azimuth-angle 154, as will be understood by those in theart.

FIG. 12 illustrates a non-limiting example of the driver-fatiguealgorithm that may be stored in the memory of the controller 32. Thedriver-fatigue algorithm may include logic that includes makingdecisions based on sensor input, lane-departure-warnings,steering-wheel-activity, and host-vehicle-speed.

Accordingly, a driver-fatigue warning system 10, a controller 32 for thedriver-fatigue warning system 10 and a method 200 of operating thedriver-fatigue warning system 10 is provided. The system 10 reduces therates of the false driver-fatigue warning by determining when to count42 the lane-departure 38, which may help to reduce occurrences ofoperators 30 intentionally deactivating the driver-fatigue warningsystem 10. By not counting 42 the occurrences of the lane-departures 38under the conditions described above, the system 10 does not penalizethe operator 30 of the host-vehicle 12 when the operator 30 makes anintentional lane-departure 38. The operator 30 may make the intentionallane-departure 38 to provide greater clearance between the host-vehicle12 and the detected object 22 that may be perceived as a hazard by theoperator 30.

While this invention has been described in terms of the preferredembodiments thereof, it is not intended to be so limited, but ratheronly to the extent set forth in the claims that follow.

We claim:
 1. A warning system, the system comprising: a camera; analert-device; and a controller in communication with the camera and thealert-device, said controller counts a lane-departure of a host-vehiclewhen a host-vehicle-offset relative to a lane-marking is less than athreshold, does not count the lane-departure when an object in a roadwayurges an operator of the host-vehicle to perform the lane-departure, andactivates the alert-device when the count of the lane-departures exceedsa departure-threshold.
 2. The system of claim 1, wherein the object isanother vehicle.
 3. The system of claim 2, wherein the other vehicle istraveling in an adjacent-lane to a travel-lane traveled by thehost-vehicle.
 4. The system of claim 2, wherein the other vehicle istraveling at least partially in a travel-lane traveled by thehost-vehicle.
 5. The system of claim 1, wherein the object is astationary object.
 6. The system of claim 5, wherein the stationaryobject is adjacent to a travel-lane traveled by the host-vehicle.
 7. Thesystem of claim 5, wherein the stationary object is at least partiallyin a travel-lane traveled by the host-vehicle.
 8. The system of claim 1,wherein the controller further determines that the object is in anadjacent-lane and counts the lane-departure when the lane-departure isinto the adjacent-lane.
 9. The system of claim 1, wherein thedeparture-threshold comprises a number of occurrences of lane-departureswithin a defined time-period.
 10. The system of claim 9, wherein thedeparture-threshold is in a range from between 2 to 3 lane-departures,and wherein the time-period is two minutes.
 11. A method of operating awarning system, the method comprising: counting, with a controller incommunication with a camera and an alert-device, a lane-departure of ahost-vehicle when a host-vehicle-offset relative to a lane-marking isless than a threshold; ignoring, with the controller, the lane-departurewhen an object in a roadway urges an operator of the host-vehicle toperform the lane-departure; and activating, with the controller, thealert-device when the count of the lane-departures exceeds adeparture-threshold.
 12. The method of claim 11, wherein the object isanother vehicle.
 13. The method of claim 12, wherein the other vehicleis traveling in an adjacent-lane to a travel-lane traveled by thehost-vehicle.
 14. The method of claim 12, wherein the other vehicle istraveling at least partially in a travel-lane traveled by thehost-vehicle.
 15. The method of claim 11, wherein the object is astationary object.
 16. The method of claim 15, wherein the stationaryobject is adjacent to a travel-lane traveled by the host-vehicle. 17.The method of claim 15, wherein the stationary object is at leastpartially in a travel-lane traveled by the host-vehicle.
 18. The methodof claim 11, wherein the controller further determines that the objectis in an adjacent-lane and counts the lane-departure when thelane-departure is into the adjacent-lane.
 19. The method of claim 11,wherein the departure-threshold comprises a number of occurrences oflane-departures within a defined time-period.
 20. The method of claim19, wherein the departure-threshold is in a range from between 2 to 3lane-departures, and wherein the time-period is two minutes.